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My Ride: E61 550i manual gear, panoramic roof, dark blue
Model Year: 2006
Engine: N62 4.8
Center brake-light repair
Hello gents,
The center brake light contains 26 transparant red lights with a voltage drop on each of just above 2 volts which seems pretty normal. The leds tend to fail over time and if you want to fix it you'll have to buy the whole unit for around € 160,- to € 200,- which is of course ridicolous....So the good news is you can fix it yourself by just replacing the leds.
Attached the wiring scheme. Note: the current of first 2 leds in series is controlled by a 142 ohm resistor while all the others are wired in 6 batches of 4 leds in series with the current controlled by a resistor of 74 ohm.
To 2 normal diodes directly after the (+) and or the resistors don't tend to fail and will last as long as you live. The leds do fail and create a voltage drop over the led of around 7 volt (with me at least)...causing all the other leds in the same series to NOT light up as well.
I'm gonna replace all leds and close the cut out transparant plastic with I don't know what yet.....
Well done! I thought maybe you had wiring issues that caused the brake light to go out at first....but I bet you tested that. Thanks for sharing the knowledge!